that man arrested for terrorizing highway drivers across michigan. 40-year-old raulie wayne casteel, was arrested for wounding one and leaving countless on-edge. Reporter: You can bet this morning's commute along the i-96 corridor through four michigan counties will be less terrifying today. Drivers worried about traffic instead of bullets. Investigators say they got their man. And it's a shocker. He is a husband, father of a preschaged daughter. And according to police this morning, he is the i-96 shooter. Police 43-year-old raulie casteel is responsible for 24 shootings since mid-october. We have the individual we believe to be responsible. Reporter: Casteel was arrested after a raid on his wixom home tuesday night. Police say they found handguns used to shoot holes on a terror spree. Miraculously, only one person was hit. That person seen here, on surveillance video, limping into a gas station, looking for help. We had so many people afraid to travel down i-96. We had parents pulling their kids out of schools. Reporter: It was the bullet in this car that police say led them to their big break. The woman, luck to be alive, identified the shooter's car. Giving a partial license plate. We used policework to find the lead for us to get this guy. Reporter: But the motive remains a mystery. Raulie casteel is a university of michigan state graduate. The family man has no prior arrest record. But his relatives talk of problems. His own mother telling "the detroit free press," she worried he was mentally ill but refused to get help. Casteel's aunt telling "the detroit news," he was scared the government was after him. There were statements made by family members with respect to his mental health. We're looking into that, as well. Reporter: The judge entered the not guilty plea for casteel. Additional charges are expected. He's being held on $2 million bond. Eluding investigators, the troubling question, why? What motivated the terrifying shooting spree?

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